1. Field of the Invention
The present invention relates to a processor, a memory, a computer system, a system large scale integrated circuit (LSI), and a method of authentication.
2. Description of the Related Art
Computers are incorporated into various devices such as digital cameras, digital televisions, digital versatile disk (DVD) players, DVD/HDD recorders, game consoles, portable telephones, portable audio players, and control units of automobiles. The devices and the systems incorporating the computer process the data which includes contents whose copyrights need to be protected. In addition, these devices and systems handle important information such as personal information and charging information.
While using these devices and systems, the user might commit illegal acts such as illegal alteration of the device and system, illegal copying of decrypted contents, execution of illegal programs for acquisition of personal information, and alteration of charging information, which is increasingly problematic.
A conventional technique aims at protecting the device and the system from illegal acts by resin coating a substrate on which an LSI chip is incorporated in the device or the system, fabricating a hard-to-disassemble casing for the device, for example, thereby making the alteration more difficult.
According to another conventional technique, a Digital Signal Processor (DSP) reads out boot software from an internal Read Only Memory (ROM), and the boot software authenticates the device based on device/maker identification codes. Only when the device is authenticated, the boot is executed (see, Japanese Patent Application Laid-Open 2003-108257, for example).
Further, according to sill another conventional technique, secure booting blocks an execution of program codes other than authenticated legal program codes to prevent an execution of overwritten illegal program codes. A. security chip called Trusted Platform Module (TPM) is known to be employed for the implementation of the secure booting.
The resin coating and the enforcement of the casing are not advantageous since they increase manufacturing cost and are easily nullified by a special processing technique.
On the other hand, the secure booting also has some disadvantages as it requires a specific hardware module such as the TPM. The TPM of each device has a specific encryption key which is different from device to device. Hence, when a program which is executed on the device needs to be updated, an updated program to be distributed must be constructed so as to allow for the authentication by different encryption keys of respective devices, whereby the maintenance cost significantly increases.
In addition, though the secure booting can confirm the activation of a predetermined program, is unable to readily detect program leakage or the alteration of the hardware.